The entire thesis behind the sunnah (ahadith) is that it is the explanation of the quran.

Really?

Which verse is this hadith explaining?:

Abu Huraira reported that Allah's Messenger (ﷺ) said: A group of Bani Isra'il was lost. I do not know what happened to it, but I think (that it 'underwent a process of metamorphosis) and assumed the shape of rats. Don't you see when the milk of the camel is placed before them, these do not drink and when the milk of goat is placed before them, these do drink. Abu Huraira said: I narrated this very hadith to Ka'b and he said: Did you hear this from Allah's Messenger (ﷺ)? I (Abu Huraira) said: Yes. He said this again and again, and I said: Have I read Torah? This hadith has been transmitted on the authority of Ishaq with a slight variation of wording.

But in all seriousness, what is the proof for what you said? You need to give proof from Qur'an, not Hadith.

Simple example, quran makes prayer obligatory, but doesn't tell us how to pray - that's in the hadith.

We get how to pray from mass transmission of practice from generation to generation. Like where is Makkah? Or where is China? Thousands and thousands of people were learning during the time of the prophet and teaching others. That's how it reached us.

Do you have a Sahih hadith telling you where is Makkah? Because we don't need hadith for such mass-transmitted stuff.